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Abstract

Background: Stereotactic breast biopsies (SBB) are associated with significant anxiety. As anxiolytic medication is not a viable option for many patients, nonpharmacologic methods to manage acute anxiety in this setting are needed.
Method: In this single-blind trial, we examined feasibility and acceptability, as well as the efficacy of guided meditation (GM) compared to guided focused breathing (FB), both delivered for 10 min before and throughout SBB, and standard care (SC), on anxiety and pain ratings, blood pressure, pulse, and brain activity in women undergoing SBB. Patients were recruited prior to SBB and randomized in a 2:2:1 ratio to GM (n=30), FB (n=30), or SC (n=16). Anxiety, pain, blood pressure, and pulse activity were assessed at baseline, after a 10-min pre-SBB group-specific activity (GM, FB, or SC (listening to neutral audio clips)), and post-SBB. Anxiety and pain were also assessed every 4 min during SBB, and electroencephalogram (EEG) activity was collected throughout the study. Baseline trait mindfulness was examined as a moderator of the intervention.
Results: Fifty-four percent (84/157) of eligible patients provided consent for the present study, and 90% (76/84) of consented patients were evaluable. Linear multilevel modeling covarying for baseline anxiety ratings revealed a significant group by time interaction on change in anxiety ratings during the procedure (p < 0.001). Women in GM reported a steeper reduction in anxiety during the biopsy compared to FB (β = -0.09, p = 0.001) and SC (β = -0.12, p = 0.001), while FB and SC reported similar reductions in anxiety during biopsy (p = 0.65). There were no group differences in pain ratings during the biopsy, and no group differences on any measure after the 10-min group-specific activity or after the biopsy. Moderation analyses indicated that participating in GM buffered the effect of low trait mindfulness on anxiety before and during biopsy and pain after biopsy.
During biopsy, GM had greater delta wave activity in the left primary somatosensory cortex (S1), medial prefrontal cortex (PFC), insula, and bilateral precuneus compared to SC. FB had greater delta activity than both GM and SC in the bilateral S1, anterior PFC, insula, and precuneus, and left medial PFC during biopsy. Further, delta wave activity in the left medial PFC negatively correlated with anxiety, and delta wave activity in the left S1, insula, and precuneus negatively correlated with pain ratings reported during biopsy. Additionally, GM had greater theta wave activity in the right medial and anterior PFC compared to SC. Similarly, FB had greater theta wave activity in the bilateral anterior PFC, right medial PFC, and right insula and compared to SC. Theta activity in these regions was not associated with anxiety or pain ratings during biopsy. Groups did not differ in any other bandwidth during biopsy.
Conclusion: Results indicate GM is a feasible and accepted intervention. Additionally, GM relieves anxiety during biopsy more effectively than FB and SC. Compared to SC, both GM and FB were associated with neuronal quieting (i.e., greater slow-wave activity) in regions associated with pain processing, emotional and cognitive engagement, and self-awareness. Lastly, participation in GM appears to be particularly useful for individuals who report low trait mindfulness, suggesting even transient increases in mindfulness may be beneficial in acutely stressful settings.